Metallic powders for use as electrode material in multilayer ceramic capacitors and method of manufacturing and of using same

ABSTRACT

The present disclosure generally relates to metallic powders for use in multilayer ceramic capacitors, to multilayer ceramic capacitors containing same and to methods of manufacturing such powders and capacitors. The disclosure addresses the problem of having better controlled smaller particle size distribution, with minimal contaminant contents which can be implemented at an industrial scale.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. provisional patentapplication Ser. No. 62/623,708 filed on Jan. 30, 2018. The contents ofthe above-referenced document are incorporated herein by reference intheir entirety for all purposes.

FIELD OF TECHNOLOGY

The present disclosure generally relates to metallic powders for use aselectrode material in multilayer ceramic capacitors, to multilayerceramic capacitors containing same and to methods of manufacturing suchpowders and capacitors.

BACKGROUND INFORMATION

Recently, in mobile electronic equipment such as cellular phones andpersonal computers, trends toward miniaturization, higher performance,and lower electric power consumption have become increasingly prominent.Integration and miniaturization into chips of passive components such ascapacitors, inductors, and resistors used in these pieces of equipmenthave also been accelerated. Conventionally, single-layer ceramiccapacitors such as disk and cylindrical-type capacitors have beenprimarily used. However, the use of multilayer ceramic capacitors(MLCCs) prevails nowadays, because of their properties of highcapacitance with small size, high reliability, and excellenthigh-frequency characteristics. The quantity of shipment of MLCCs hasgrown annually due to the rapid increase of the production of cellularphones and computers, and the demand will further increase in thefuture.

Traditional MLCCs use copper for their external electrodes, noble metalssuch as silver or palladium for their inner electrodes and a ceramicacting as the dielectric. Over the past years, nickel electrodes havebeen replacing palladium bearing electrodes. This limited the relianceon palladium, which was relatively expensive, and enabled MLCCmanufacturers to cost effectively produce MLCC in much highercapacitance ranges and compete with manufacturers of tantalum capacitorsand other electrolytic capacitors.

Base metals used for manufacturing the electrodes are typically providedin paste or in powder. The base metals generally need to be sintered toform the internal electrodes of MLCCs. However, in order to producerelatively small MLCCs, to control the capacitance of the MLCCs in arelatively precise manner, and to facilitate the manufacturing of theMLCCs, the base metal needs to be provided in particles of a relativelysmall size, with a relatively low concentration of contaminants, and thesize of the base metal needs to be relatively tightly controlled.

JP 2004-292950 has proposed a nickel-based fine powder in which theaverage particle diameter is ranging from 0.05 μm to 0.3 μm. However,the manufacturing process described in JP 2004-292950 makes use of avapor phase reduction of nickel chloride vapor which results in ametallic powder contaminated with chlorine. In order to remove thechlorine, it is necessary to rinse with water, which increases particleaggregation and results in a particle size distribution which is skewedtowards larger particle media sizes. This is why the number of particlesobtained in JP 2004-292950 that have a particle diameter of 0.6 times orsmaller than the average particle diameter is 10% or less and thatparticles having a size of 1 μm or more can be as high as 721 ppm.

JP 2001-073007 has proposed a nickel-based fine powder having an averageparticle diameter ranging from of 0.1 μm to 1.0 μm and having a coarseparticle having a particle diameter of 2 μm or more of 700 ppm.Similarly to the situation in JP 2004-292950, this document makes use ofa vapor phase reduction of nickel chloride vapor which results in ametallic powder contaminated with chlorine. In order to remove thechlorine, it is necessary to rinse with water, which increases particleaggregation and results in a particle size distribution which is alsoskewed towards larger particle media sizes.

The metallic powders and process of manufacturing same proposed in thesedocuments are, therefore, not satisfactory due to the presence of largerparticle size which increases the probability of defective productsoccurrence at the time of manufacturing MLCCs.

As such, there is still a need in the field for metallic powders for usein multilayer ceramic capacitors that have a better controlled smallerparticle size distribution and that can be produced efficiently and costeffectively on an industrial scale.

SUMMARY OF DISCLOSURE

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key aspects oressential aspects of the claimed subject matter.

As embodied and broadly described herein, the present disclosure relatesto a composition in particulate form for use in an electrode layer of amultilayer ceramic capacitor (MLCC), the composition comprisingmetal-based spherical particles doped with a doping agent that operatesto increase the sintering temperature of the composition, and comprisingless than 1000 ppm of carbon content, wherein the particles have amedian size (D50) of ≤120 nm.

As embodied and broadly described herein, the present disclosure relatesto a composition in particulate form for use in an electrode layer of amultilayer ceramic capacitor (MLCC), the composition comprisingmetal-based spherical particles doped with a doping agent that operatesto increase the sintering temperature of the composition, and comprisingless than 1000 ppm of carbon content, wherein the particles have aparticle size distribution (PSD) of 20 nm to 350 nm.

As embodied and broadly described herein, the present disclosure relatesto a composition in particulate form for use in an electrode layer of amultilayer ceramic capacitor (MLCC), the composition comprisingmetal-based spherical particles doped with a doping agent that operatesto increase the sintering temperature of the composition, and comprisingless than 1000 ppm of carbon content, wherein the particles have aparticle size distribution (PSD) of 20 nm to 300 nm, with particleshaving a size >350 nm representing less than 1 ppm.

As embodied and broadly described herein, the present disclosure relatesto a composition in particulate form for use in an electrode layer of amultilayer ceramic capacitor (MLCC), the composition comprisingmetal-based spherical particles doped with a doping agent that operatesto increase the sintering temperature of the composition, and comprisingless than 1000 ppm of carbon content, wherein the particles have aD99≤250 nm.

As embodied and broadly described herein, the present disclosure relatesto a multilayer ceramic capacitor (MLCC) comprising a plurality ofdielectric layers and electrode layers arranged to form a stack were thedielectric layers and the electrode layers alternate, one or more of theelectrode layers being formed from a precursor layer including thecomposition as described herein.

As embodied and broadly described herein, the present disclosure relatesto a process for obtaining a composition in particulate form for use inan electrode layer of a multilayer ceramic capacitor (MLCC), the processcomprising providing metal-based particles doped with a doping agentthat operates to increase the sintering temperature of the composition,vaporizing the metal-based particles to obtain the metal and dopingagent in vapor form and cooling the metal and doping agent in vapor formso as to obtain the composition in particulate form for use in the MLCCwherein the composition comprises less than 1000 ppm of carbon content,and wherein the particles have a median size (D50) of ≤120 nm.

As embodied and broadly described herein, the present disclosure relatesto a process for obtaining a composition in particulate form for use inan electrode layer of a multilayer ceramic capacitor (MLCC), the processcomprising providing metal-based particles doped with a doping agentthat operates to increase the sintering temperature of the composition,vaporizing the metal-based particles to obtain the metal and dopingagent in vapor form and cooling the metal and doping agent in vapor formso as to obtain the composition in particulate form for use in the MLCCwherein the composition comprises less than 1000 ppm of carbon content,and wherein the particles have a particle size distribution (PSD) of 20nm to 350 nm and a D90 of ≤200 nm.

As embodied and broadly described herein, the present disclosure relatesto a process for obtaining a composition in particulate form for use inan electrode layer of a multilayer ceramic capacitor (MLCC), the processcomprising providing metal-based particles doped with a doping agentthat operates to increase the sintering temperature of the composition,vaporizing the metal-based particles to obtain the metal and dopingagent in vapor form and cooling the metal and doping agent in vapor formso as to obtain the composition in particulate form for use in the MLCCwherein the composition comprises particles having a particle sizedistribution (PSD) of 20 nm to 300 nm, with particles having a size >350nm representing less than 1 ppm.

As embodied and broadly described herein, the present disclosure relatesto a process for obtaining a composition in particulate form for use inan electrode layer of a multilayer ceramic capacitor (MLCC), the processcomprising providing metal-based precursor particles doped with a dopingagent that operates to increase the sintering temperature of thecomposition, vaporizing the metal-based precursor particles to obtainthe metal and doping agent in vapor form and cooling the metal anddoping agent in vapor form so as to obtain the composition inparticulate form for use in the MLCC wherein the composition comprisesless than 1000 ppm of carbon content and particles having a D99≤250 nm.

As embodied and broadly described herein, the present disclosure relatesto a process for providing the metal-based precursor particles dopedwith the doping agent as described herein, comprising mixing the dopingagent with molten metal to obtain a molten metal-doping agent mixture;and atomizing the mixture to obtain the metal-based precursor particlesdoped with the doping agent.

All features of exemplary embodiments which are described in thisdisclosure and ae not mutually exclusive can be combined with oneanother. Elements of one embodiment can be utilized in the otherembodiments without further mention. Other aspects and features of thepresent technology will become apparent to those ordinarily skilled inthe art upon review of the following description of specific embodimentsin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of specific embodiments is provided herein belowwith reference to the accompanying drawings in which:

FIG. 1 is a flowchart illustrating a process for manufacturing acomposition for use in a multi-layer ceramic capacitor (MLCC) inaccordance with an embodiment of the present disclosure;

FIG. 2 is a flowchart illustrating a process for obtaining metal-basedprecursor particles for use in the process of FIG. 1 in accordance withan embodiment of the present disclosure;

FIG. 3 is a flowchart illustrating a process implementing the processesof FIG. 1 and FIG. 2 for obtaining nickel-based particles doped withsulfur in accordance with an embodiment of the present disclosure;

FIG. 4 is a scanning electronic microscope image of a compositioncomprising nickel-based particles obtained with the process of FIG. 1;

FIGS. 5A, 5B and 5C are scanning electronic microscope (SEM) images of acomposition comprising nickel-based particles obtained with the processof FIG. 1, before classification;

FIG. 6 is a schematic representation of a MLCC in accordance with anembodiment of the present disclosure;

FIG. 7 is a cross section of the MLCC of FIG. 6 in accordance with anembodiment of the present disclosure;

FIG. 8 is a schematic representation of a cross section of the MLCC ofFIG. 6 including an internal electrode layer and dielectric layers,before a sintering process, in accordance with an embodiment of thepresent disclosure;

FIG. 9A is a schematic representation of the cross section of the MLCCof FIG. 8 after the sintering process, in accordance with an embodimentof the present disclosure;

FIG. 9B is a schematic representation of typical scanning electronicmicroscope (SEM) images that can be obtained from a cross section of theMLCC of FIG. 9A, in accordance with an embodiment of the presentdisclosure;

FIG. 10 is a schematic representation of the cross section of the MLCCof FIG. 8 where the electrode layer includes fine contaminant particles,in accordance with an embodiment of the present disclosure;

FIG. 11 is a schematic representation of the cross section of the MLCCof FIG. 10, after the sintering process, in accordance with anembodiment of the present disclosure;

FIG. 12 is a schematic representation of the cross section of the MLCCof FIG. 10, after the sintering process, comprising undesirablecompounds, in accordance with an embodiment of the present disclosure;

FIG. 13A is a first schematic representation of the cross section of theMLCC of FIG. 8, after the sintering process, comprising a cracked MLCC,in accordance with an embodiment of the present disclosure;

FIG. 13B is a second schematic representation of the cross section ofthe MLCC of FIG. 8, after the sintering process, comprising a crackedMLCC, in accordance with an embodiment of the present disclosure;

FIG. 14 is a schematic representation of a typical scanning electronicmicroscope (SEM) image of a metal-based particle showing an oxidationlayer on its surface in accordance with an embodiment of the presentdisclosure;

FIG. 15 is a graph illustrating the sintering behavior of nickel-basedparticles doped with sulfur compared to nickel-based particles without adoping agent, in accordance with an embodiment of the presentdisclosure;

FIG. 16A is a scanning electronic microscope (SEM) image of acomposition comprising nickel-based precursor particles doped withsulfur classified to retain fine sizes in accordance with an embodimentof the present disclosure;

FIG. 16B is a scanning electronic microscope (SEM) image of acomposition comprising nickel-based precursor particles doped withsulfur classified to retain coarse sizes in accordance with anembodiment of the present disclosure;

FIG. 17 is a graph illustrating particle size distribution ofnickel-based particles doped with sulfur and classified to obtain a D50of 80 nm, in accordance with an embodiment of the present disclosure;

In the drawings, exemplary embodiments are illustrated by way ofexample. It is to be expressly understood that the description anddrawings are only for the purpose of illustrating certain embodimentsand are an aid for understanding. They are not intended to be adefinition of the limits of the invention.

DETAILED DISCLOSURE

The present technology is explained in greater detail below. Thisdescription is not intended to be a detailed catalog of all thedifferent ways in which the technology may be implemented, or all thefeatures that may be added to the instant technology. For example,features illustrated with respect to one embodiment may be incorporatedinto other embodiments, and features illustrated with respect to aparticular embodiment may be deleted from that embodiment. In addition,numerous variations and additions to the various embodiments suggestedherein will be apparent to those skilled in the art in light of theinstant disclosure which variations and additions do not depart from thepresent technology. Hence, the following description is intended toillustrate some particular embodiments of the technology, and not toexhaustively specify all permutations, combinations and variationsthereof.

The present inventors have through extensive R&D work developed anddesigned compositions in particulate form for use as electrode materialin multilayer ceramic capacitors (MLCCs) and a method of manufacturingsame, where the compositions include particles having nanometric sizesthat are more suitable to the increasing demands of the industry.Indeed, since the capacitance of a MLCC is dependent to the number oflaminated layers and the thickness of the dielectric layer, it isadvantageous to ensure that the MLCC be as thin as possible. This iswhere using the compositions in particulate form described herein in themanufacturing of the electrode layer disposed between dielectric layerscan be advantageous in that these compositions have particles of smallersize with reduced coarse particles content than what has been known inthe art so far.

The compositions described herein also have reduced content ofcontaminants, such as carbon, which can result in better electrochemicalperformances of MLCCs and/or which can result in less delamination orcracks during the manufacturing of MLCCs. Indeed, typically, duringmanufacturing of MLCC, carbon on the surface of metal-based particlesmay be removed during a “bake-out” step at a temperature exceeding 200°C. where excessive amounts of carbon can cause delamination and cracksin the MLCC. Such delamination and cracks are undesirable and theirpresence will typically cause the rejection of the MLCC, thus, reducingmanufacturing productivity. Additionally or alternatively, when carbonis present inside the metal-based particles, the carbon may not beeasily removed even through the above-mentioned “bake-out” step, thus,remaining in the MLCC. Without being bound by any theory, it is believedthat this residual carbon may also cause deficiencies in the MLCC interms of long term reliability, such for example, with respect tocapacitance, DC bias, reliability, and the like.

Compositions Characteristics

In a broad non-limiting aspect, the compositions in particulate form foruse in MLCCs of the present disclosure have metal-based particles, wherethe metal can be selected from silver, copper, lead, palladium,platinum, nickel, gold, cobalt, iron, cadmium, zirconium, molybdenum,rhodium, ruthenium, tantalum, titanium, tungsten, zirconium, niobium,and the like, as well as from alloys thereof. During the manufacturingof MLCCs, these compositions can be used as powders (i.e., inparticulate form) or as slurry/pastes. Such slurry/pastes includebinders suitable for the purpose of making electrodes in MLCCs, whichare known in the art and, for conciseness sake, will not be furtherdescribed here.

In some specific implementations, the metal-based particles of thepresent disclosure can also be doped with a doping agent, which operatesto increase the sintering temperature of the metal-based particlesduring manufacture of the MLCC. During the manufacturing of MLCCs,typically, there is a sintering step where the electrode materials anddielectric ceramic materials are heated to temperatures which can reachup to about 1500° C. for a sufficient time period resulting indensification of the electrode materials and dielectric ceramicmaterials and achieving desirable conductivity properties. When thesematerials include particles, the sintering step will cause fusion atcontact points between adjacent particles. Typically, metals used in theelectrode materials have a significantly lower sintering temperaturethan that one of ceramic materials such that without the presence of atleast a doping, which operates to increase the sintering temperature ofthe metal-based particles, there will be large differences in terms ofrespective sintering onset temperatures, which may result inmicrostructures and/or by-products that may negatively impact the MLCCand/or cause an increase in manufacturing rejections. For example, whenusing nickel-based particles as electrode material and BaTiO₃ as ceramicmaterial, the sintering onset temperature for pure nickel being about150° C. and the sintering onset temperature for BaTiO₃ to obtaindesirable dielectric properties required for use in MLCCs beingtypically >1000° C., there is a significant sintering onset temperaturegap that one must avoid. This is an example where the presence of adoping agent, which operates to increase the sintering temperature ofthe metal-based particles during manufacture of the MLCCs, isadvantageous.

The doping agent can be a single material or a blend of differentmaterials. For example, the doping agent can operate to increase theonset temperature (beginning of sintering) and/or increase the sinteringoffset temperature (end of sintering). In a specific example ofimplementation, the amount of doping agent and/or the nature of thedoping agent is selected such that the onset temperature (beginning ofsintering) and/or the sintering offset temperature (end of sintering) ofthe metal-based particles sufficiently overlaps with the sinteringtemperature range of the ceramic materials.

In some embodiments, the doping agent can be homogenously distributed inthe metal-based particles and/or at the surface of the particles. Inother embodiments, the doping agent can be heterogeneously distributedin the metal-based particles and/or at the surface of the particles. Inyet other embodiments, the doping agent can be homogenously distributedin the metal-based particles and heterogeneously distributed at thesurface of the particles. In yet other embodiments, the doping agent canbe heterogeneously distributed in the metal-based particles andhomogenously distributed at the surface of the particles.

In some specific implementations, the doping agent is a high meltingpoint metal. Examples of high melting point metal, include, but are notlimited to chromium, vanadium, titanium, zirconium, niobium, tantalum,platinum, boron, ruthenium, molybdenum, tungsten, rhodium, iridium,osmium, rhenium, and their alloys or mixtures thereof. In some otherembodiments, the doping agent is a metal with a melting point higherthan the melting point of nickel. In some embodiments, the high meltingpoint metal is an oxide or a salt.

In some specific implementations, the doping agent is sulfur.

In some specific implementations, the doping agent in the metal-basedparticles includes from 0.01 to 0.5 wt. % of sulfur content.

In some specific implementations, the compositions of the presentdisclosure include nickel-based particles doped with sulfur.

In some specific implementations, the compositions of the presentdisclosure are prepared according to a process that controls the carboncontent, such that compositions include <1200 ppm. For example, thecompositions of the present disclosure can include <1000 ppm, <900 ppm,<800 ppm, <700 ppm, <600 ppm, <500 ppm, <400 ppm, <300 ppm, <200, or<100 ppm of carbon content.

In some specific implementations, the compositions of the presentdisclosure are prepared according to a process that controls the oxygencontent in the particles to obtain satisfactory electrochemicalperformance of the MLCC.

The presence of an oxidation layer on the surface of the hereindescribed metal-based particles can also positively modify dispersionand/or flowability properties of the compositions in particulate form.

In some specific implementations, the compositions of the presentdisclosure are prepared according to a process that controls the oxygencontent in the particles to up to 5 wt. % oxygen content. For example,from 0.1 wt. % to 5 wt. %. 0.1 wt. % to 3.5 wt. %, 0.1 wt. % to 2.0 wt.%, 0.1 wt. % to 1.5 wt. %, 0.1 wt. % to 0.6 wt. %. 0.2 wt. % to 5 wt. %,0.2 wt. % to 3.5 wt. %, 0.2 wt. % to 2.0 wt. %. 0.2 wt. % to 1.5 wt. %,0.2 wt. % to 0.6 wt. % oxygen content.

Without being bound by any theory, the present inventors believe thatcontrol over the oxygen content can be beneficial for a number ofreasons. For example, when the metal-based particles are nickel-basedparticles, if the nickel electrode is oxidized over a threshold level,this will cause the presence of structural defects by volume expansionduring the MLCC manufacturing process. That is, when Ni is changed intoNiO, unit cell volume increases by 169%. However, when the oxygencontent is mainly contained in a surface layer disposed on themetal-based particles, it results in an improvement in the stability andthermal behavior of the metal.

In some specific implementations, the compositions of the presentdisclosure include metal-based particles that include an oxidation layeron at least a portion of the particle surface. In some embodiments, theoxidation layer completely covers the particle surface. For example, themain portion or all of the oxygen content discussed previously may beincluded the oxidation layer. In some embodiments, the oxidation layerhas a thickness of less than 15 nm. For example, the oxidation layer canhave a thickness of from 2 nm to 10 nm, or from 2 nm to 5 nm, such asfor example a 3 nm or 4 nm oxidation layer. The person of skill willreadily understand that the thickness of the oxidation layer may be anaverage thickness in that it may vary in thickness along the surface ofthe metal-based particle. Accordingly, the thickness may be an averagethickness value as measured by electron microscopy techniques.

In some embodiments, when the metal-based particles are nickel-basedparticles doped with sulfur, the oxidation layer can include nickeloxide and nickel sulfide.

In some specific implementations, the compositions of the presentdisclosure include metal-based particles that have nanometric sizes. Forexample, the composition may include particles having a particle sizedistribution (PSD) of 15 nm to 350 nm (prior to classification) or a PSDof 20 nm to 350 nm (after classification). Such PSD is, contrary to whatis obtained with known processes in the art, tightly controlled suchthat, for example, the particles have sizes that are skewed towardssmaller sizes instead of having sizes skewed towards coarser sizes.There are clear technical benefits in obtaining such sizes (as discussedpreviously in this text) as well as economic benefits: when thecomposition in particulate form coming out of the manufacturing processhas less coarse sizes, there is less wasted material (material whichwould not make the cut-off classification values) and as such, yieldsare increased.

For example, the composition may include one or more of the followingparticle size features:

-   -   PSD of 20 nm to 350 nm, or 20 nm to 300 nm, or 20 nm to 200 nm;    -   D90≤200 nm, or D90≤150 nm, D90≤130 nm;    -   median size (D50) of ≤120 nm, or median size (D50) of ≤100 nm,        or median size (D50) of ≤80 nm, or median size (D50) of ≤50 nm;    -   particles having a size >350 nm representing less than 1 ppm;    -   D99≤250 nm, or D99≤230 nm;    -   less than 3 particles having a size >1 μm as determined from a        scanning electronic microscope (SEM) image of 5000× of the        composition, or less than 2 particles having a size >1 μm as        determined from a scanning electronic microscope (SEM) image of        5000× of the composition, or 1 or no particle having a size >1        μm as determined from a scanning electronic microscope (SEM)        image of 5000× of the composition;    -   less than 3 particles having a size >650 nm in a scanning        electronic microscope image of 5000× of the composition, or less        than 2 particles having a size >1 μm as determined from a        scanning electronic microscope (SEM) image of 5000× of the        composition, or 1 or no particle having a size >1 μm as        determined from a scanning electronic microscope (SEM) image of        5000× of the composition    -   less than 3 particles having a size >350 nm in a scanning        electronic microscope image of 5000× of the composition, or less        than 2 particles having a size >1 μm as determined from a        scanning electronic microscope (SEM) image of 5000× of the        composition, or 1 or no particle having a size >1 μm as        determined from a scanning electronic microscope (SEM) image of        5000× of the composition.

The person of skill will appreciate that the SEM image is an image of apredetermined area of the composition being analyzed, which will varydepending on at least the D50 of the composition to ensure accuracyand/or statistical significance. For example, a D50 of 120 nm canrequire a 5 μm per 5 μm area, whereas a D50 of 80 nm can require a 3 μmper 3 μm area and a D50 of 50 nm can require a 2 μm per 2 μm area of thecomposition.

Particle size features of a composition in particulate form can bedetermined using techniques well known in the art, such as, but notlimited to, laser diffraction spectroscopy, transmission electronmicroscopy, scanning electron microscopy (SEM), and the like. Suchtechniques are well known and for conciseness sake, will not be furtherdescribed here.

Multilayer Ceramic Capacitor (MLCC)

In a broad non-limiting aspect, the compositions in particulate formdescribed herein allow one to manufacture MLCCs having advantageousproperties. MLCCs typically include a ceramic body including dielectriclayers. MLCCs also include a plurality of internal electrode layersdisposed within the ceramic body, having at least one of the dielectriclayers interposed there between, stacked along a thickness direction,being parallel with respect to an external surface, such as a mountingsurface.

FIG. 6 and FIG. 7 illustrate MLCC 270 including a plurality ofdielectric layers 274 in accordance with an embodiment of the presentdisclosure. The dielectric layers 274 may include a ceramic materialhaving high permittivity, for example, a composition including bariumtitanate (BaTiO₃)-based particles or strontium titanate (SrTiO₃)-basedparticles. MLCC 270 includes a plurality of internal electrodes 276,where each internal electrode 276 is disposed between two dielectriclayers 274 which comprise ceramic material 284 (as shown in FIG. 8). Theinternal electrodes 276 are made using a composition 230 comprisingmetal-based particles 240. FIG. 8 shows a plurality of particles 240before sintering. FIG. 9A illustrates the MLCC 270 of FIG. 8, but aftersintering, where the particles 240 of composition 230 have fused atcontact points between the particles, partially deforming to the pointof not being perfectly spherical any more, as best shown in the pictureillustrated in FIG. 9B. The person of skill will readily realize thatthe composition 230 can take the form of a slurry/paste which is spreadon the surface of the dielectric layers 274, which slurry/paste mayinclude a number of additional ingredients such as organic solvent(s)and binder resin(s).

Typically, the capacitance of a MLCC is dependent to the number oflaminated layers and to the thickness of the dielectric layer, and assuch, it is advantageous to ensure that the MLCC be as thin as possible.This is where using the composition in particulate form described hereinin the manufacturing of the electrode layers disposed between dielectriclayers can be advantageous in that this composition has particles ofsmaller size with reduced coarse particles content than what has beenknown in the art so far, thus, allowing one to reduce the overallthickness of MLCCs.

For example, when using the composition of the present disclosure, onecan manufacture a MLCC where on a cross section 7A of the ceramic bodyin a direction perpendicular to the mounting surface, as shown forexample in FIG. 6 and FIG. 7, two adjacent dielectric layers 274separated by an internal electrode layer 276 can have an averagedistance d of <800 nm between respective points intersecting an axis 290perpendicular to the mounting surface. This distance d can be forexample <500 nm, <400 nm, <300 nm, or a distance of >100 nm. Thisdistance d is shown in FIG. 9B.

In order to manufacture standardized MLCCs, each internal electrode 276as illustrated in FIGS. 9A and 9B requires a certain average number ofparticles 240 to allow the internal electrodes 276 to have relativelyuniform thickness, which is advantageously as thin as possible. Theaverage number of particles 240 of internal electrode 276 may beassessed in a number of ways. For example, one can dissect the MLCCalong axes 7A as shown in FIG. 6 to obtain a cross section of theceramic body in a direction perpendicular to the external surface asshown in FIG. 7. In this cross section, one can determine the number ofparticles 240 in a number of electrodes 276 over a pre-determined number(e.g., 25, 36, 64, etc.) of locations which cross axis 290 which isperpendicular to the plurality of electrodes 276 as shown in FIG. 7 andaveraging the obtained values. The composition in particulate form ofthe present disclosure has a particle size distribution such that anelectrode layer interposed between two adjacent dielectric layers priorto a sintering process includes from 2 to 8 metal-based sphericalparticles disposed in a direction parallel to the axis 290, such as from3 to 5 metal-based spherical particles.

If the average number of particles 240 in a given electrode layer 276throughout various locations crossing respective axes 290 is notconsistent throughout, e.g., the standard deviation is too high, someportions of the given internal electrode 276 will significantly bethicker than other portions, which may translate into inconsistentelectrical properties and/or out-of-spec MLCC. At least for this reason,the herein described composition in particulate form having thepreviously discussed size features is advantageous—in the presentinvention, there is clearly more control over the particle size featuresand, thus, less variability in terms of electrical properties andthickness of MLCC. This control over the particle size features thus mayresult in less out-of-spec MLCC, thus, reducing defective fractions inproduction batches and increasing productivity.

The person of skill will readily understand that the metal-basedparticles will not retain the spherical shape after sintering (as shownin FIG. 9B), since the particles are somewhat deformed due to materialfusion and compression at the contact points between the particles.Nevertheless, after sintering, the particles are still recognizable asmore or less discrete particles and one can typically still assess thenumber of particles disposed in a direction parallel to the crosssection.

Process of Manufacture of the Composition

In a broad non-limiting aspect, the compositions in particulate formdescribed herein can be manufactured using a process that vaporizesprecursor materials so as to obtain a gas containing the precursors invapor form. The present inventors have developed a process which allowsone to control the residence time of the precursor materials in thevaporization zone so as to sufficiently vaporize the precursors toensure that there are no remaining precursors in solid form after themanufacturing process, which can be undesirable in particular when suchprecursors include particles in micron size that would find their wayinto the composition in particulate form and thus skew its PSD towardscoarser sizes.

The present inventors have also developed a way to control the coolingrate of the gas containing the precursors in vapor form so as to obtaina herein described composition in particulate form having the desiredparticle size features discussed previously.

FIG. 1 illustrates a process 20 for manufacturing a composition inparticulate form described herein in accordance with an embodiment ofthe present disclosure. The process 20 includes step 22 of evaporatingprecursor materials (e.g., metal and doping agent) to obtain a gascontaining the precursor materials in vapor form. For example, step 22may be implemented using an inductively coupled plasma torch (ICP torch)(e.g., TEKNA PL-50, PN-50, PL-35, PN-35, PL-70, PN-70, PN-100) or adirect current (DC) plasma torch (e.g., those commercialized by Praxair,Oerlikon-Metco, Pyrogenesis or Northwest Mettech).

Advantageously, the process 20 is designed so as to optimize theresidence time of the precursor materials into the plasma reaction zoneof the torch to cause sufficient evaporation of the precursor materialsto ensure that there are no precursor materials in solid form entrainedin the gas containing the precursor materials in vapor form. Forexample, when the process 20 is implemented in an ICP torch, precursormaterials in solid form entrained in the gas containing the precursormaterials in vapor form could interfere with the desired PSD and resultin particles having coarse particle sizes.

In some embodiments, the residence time of the precursor materials intothe plasma reaction zone of the torch may be controlled and optimized bycontrolling the precursor materials feeding rate into the plasmareaction zone. In some embodiments, the precursor materials feeding ratemay be controlled through controlling operational parameters for thefeeding device, such as motor RPM if it is a rotating distributiondevice, vibration parameters if it is a vibration motor device, and thelike. For example, the present inventors have discovered that a feedingrate in the range of 10 to 35 g/min of precursor materials in particleform through a ¼ inch feeding tube which is consistent in time (notvarying in time by more than 1%) affords best results with an ICP torch.

The present inventors have also discovered that while using a carriergas to transport precursor materials from the feeding inlet into theplasma reaction zone at more or less high speeds can be useful toprevent settlement within the transport circuit and thus preventclogging of the system, a carrier gas flow rate which is too highresults in particle speeds which are also too high, thus, reducingresidence time of the precursor materials into the plasma reaction zone.For example, the present inventors have discovered that a flow rate ofcarrier gas at a consistent (i.e., not varying in time by more than 1%)flow rate ≤10 L/min in a feeding tube of a ¼ inch inner diameter. Thecarrier gas flow rate can be manually controlled or using a computerizedsystem.

In some embodiments, an additive gas (e.g., oxygen) can be incorporatedin a controlled manner into the process so as to obtain from 0.1 wt. %to 5 wt. % oxygen content in the metal-based particles. For example, theadditive gas (e.g., oxygen) can cause formation of an oxide layer on thesurface of particles having a thickness of less than 15 nm, such as lessthan 10 nm, less than 5 nm, such as 2 to 4 nm. The additive gas (e.g.,oxygen) can have a consistent (i.e., not varying in time by more than1%) flow rate so as to obtain such oxygen content and/or oxidativelayer. For example, the additive gas flow rate can be in the range of0.5 to 1.5 L/min.

There are several ways of obtaining the precursor materials used in step22. One embodiment will now be discussed with reference to FIG. 2.

FIG. 2 outlines an atomization process 10, which can be used forobtaining metal-based precursor particles doped with the doping agent inaccordance with an embodiment of the present disclosure. Atomizationprocesses are known in the art, such as gas atomization. DC plasmaatomization, inductively coupled plasma atomization, and the like, andas such, details of the systems used to implement the atomizationprocess 10 will not be described in great detail here.

The atomization process 10 includes a step 12 of dissolving the dopingagent in molten metal to obtain a molten metal/doping agent mixture. Asdiscussed previously, the doping agent may be a single doping agent or ablend of doping agents. Optionally, the process 10 may include a step(not shown) of assessing a concentration of doping agent present in themolten metal/doping agent mixture and, if necessary, adjusting theconcentration of doping agent to compensate for any loss of doping agentthrough, for example, volatilization caused by the high meltingtemperatures used to obtain the mixture. The doping agent concentrationin the mixture is controlled so as to obtain metal-based precursorparticles doped with, for example, from 0.01 to 0.5 wt. % of dopingagent.

The molten metal/doping agent mixture is then atomized at a step 14 toform metal-based precursor particles doped with the doping agent.Typically, the precursor particles obtained at this step will have a PSDincluding micron sizes. Typically, the metal-based precursor particlesobtained with atomization process 10 are substantially spherical. Inother words, the particles have a degree of deviation from perfectspherical shape that is sufficiently small so as to not measurablydetract therefrom. The exact degree of deviation allowable may in somecases depend on the specific context.

The process 10 may then include a sieving (e.g., using sievingmembranes, or mesh or cloth) or gas-classification step 16 to retain aparticle size distribution of interest. In some instances, an inert gasclassification system can be used to obtain the desired particle sizedistribution. In some embodiments, the metal-based precursor particlesdoped with the doping agent have a particle size distribution (PSD) offrom 1 μm to 200 μm, or any PSD within such range. In some embodiments,the metal-based precursor particles doped with the doping agent have anaverage median (D50) size in the range of from 1 μm to 25 μm, or from 1μm to 15 μm, or from 1 μm to 10 μm, or from 5 μm to 25 μm, or from 5 μmto 15 μm, or from 5 μm to 10 μm, and the like. In some embodiments, themetal-based precursor particles doped with the doping agent have a D90particle size distribution <50 μm, or <45 μm, or <40 μm, or <35 μm, or<30 μm, or <25 μm and the like. In some embodiment, the metal-basedprecursor particles doped with the doping agent have a specific surfacearea (SSA) as measured by the Brunauer-Emmett-Teller adsorption method(BET) that is at least 0.15 m²/g, or at least 0.20 m²/g, or at least0.25 m²/g, and the like. Techniques for sieving (e.g., using sievingmembranes, or mesh or cloth) or gas-classification are well known in theart, and as such, will not be further described here.

In some specific implementations, the process 10 is implemented in asystem that does not make use of graphite-containing elements in zonesof high heat so as to minimize contamination of the metal-basedprecursor particles with high contents of carbon. For example, themetal-based precursor particles produced with the atomization process 10will contain less than 1200 ppm, or less than 1000 ppm, or less than 900ppm, or less than 800 ppm, or less than 700 ppm, or less than 600 ppm,or less than 500 ppm, or less than 400 ppm, or less than 300 ppm, orless than 200 ppm of carbon content. Examples of suitable atomizationsystems for implementing such process are described, for example, in anyone of U.S. Pat. Nos. 9,718,131; 5,707,419; WO 2011/054113, WO2017/011900, WO 2017/070779; WO 2017/177315; and WO 2016/191854, whichare all incorporated herein by reference for all purposes.

In some embodiment, the metal-based precursor particles produced withthe atomization process 10 will contain from 0.1 wt. % to 5 wt. % oxygencontent, such as up to 3.5 wt. %, up to 2.0 wt. %, up to 1.5 wt. %, upto 0.6 wt. %, and the like.

In some embodiment, the metal-based precursor particles produced withthe atomization process 10 are substantially pure. In other words, themetal-based precursor particles do not include significant undesiredcomponents levels, such as <0.5 wt. %. <1 wt. %. <2 wt. %, <3 wt. %, <4wt. %. <5 wt. %, <6 wt. %. <7 wt. %, <8 wt. %. <9 wt. % or <10 wt. %undesired components.

As the person of skill will readily understand, the process 10advantageously produces metal-based particles which are used as carriersfor the doping agent.

Returning to FIG. 1, the process 20 for manufacturing the composition inparticulate form includes a step 24 of cooling the gas containing theprecursor materials in vapor form so as to cause the metal and dopingagent to recombine and obtain a composition in particulate form. Forinstance, in some examples, a cooling rate may be controlled such as toobtain the metal-based particles of the present disclosure. In someinstances, the cooling rate may be controlled such that the gastemperatures are reduced to below about 350° C. In some instances,vaporized metal and doping agent are cooled down in a controlled mannerusing a quench gas having a consistent (i.e., not varying in time bymore than 1%) flow rate so as to obtain the desired particle sizedistribution. For example, the quench gas can be incorporated into theprocess at a consistent flow rate in the range of 1000 to 8000 L/min soas to obtain the desired particle size distribution.

The process 20 may also include a classification step (not show) todiscard particles having a size <20 nm such as particles 248 illustratedin FIG. 10. Without being bound by any theory, the presence of particles248 may be problematic in that their presence may interfere withadditives that are typically added to the electrode materialslurry/paste when manufacturing MLCC, such as BaTiO₃ which typicallyalso have a size <20 nm. In other words, when manufacturing MLCC, it isdesirable to have the additives fill void spaces between particles 240and as such, it is desirable to reduce as possible the content of otherparticles of similar size which would prevent these additives fromoccupying these void spaces. Alternatively or additionally, and againwithout being bound by any theory, presence of particles 248 having asize <20 nm in the composition 230 may be detrimental during thesintering step in that these may chemically react with other elementscausing a presence of undesirable compounds 290 into the internalelectrodes 276 as shown in FIG. 12, and/or fuse with adjacent particles240 (e.g. about a fused area between metal-based particles 240) as shownin FIG. 11, thereby altering the microstructure of the internalelectrodes 276, harming the electric properties of the internalelectrodes 276, and/or diminishing the quality of the internal electrode276 after sintering.

The process 20 thus offers clear advantages in preparing MLCC withreduced likelihood of rejections. As discussed previously, the process20 reduces contaminant contents, such as carbon (to levels such as <1000ppm), which when present in sufficiently high levels (>1400 ppm) in thecomposition 230, may induce the presence of cracks 290, as illustratedin FIG. 13A and shown in FIG. 13B, which increases rejection of MLCC.

Definitions

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by a person of ordinaryskill in the art to which the present invention pertains. As usedherein, and unless stated otherwise or required otherwise by context,each of the following terms shall have the definition set forth below.

As used herein, the term “dopant” and the expression “doping agent” aeused interchangeably and refer to a trace impurity elements that isinserted into a substance (in very low concentrations) to modify thethermodynamic and/or electrical and/or optical properties of thesubstance.

As used herein, the term “alloy” refers to a mixture of metals or amixture of a metal and another element. Alloys are defined by a metallicbonding character. An alloy may be a solid solution of metal elements (asingle phase) or a mixture of metallic phases (two or more solutions).Intermetallic compounds are alloys with a defined stoichiometry andcrystal structure.

As used herein, the term “plasma” refers to a state of matter in whichan ionized gaseous substance becomes highly electrically conductive tothe point that long-range electric and magnetic fields dominate thebehavior of the matter. Plasma is typically artificially generated byheating neutral gases or by subjecting that gas to a strongelectromagnetic field.

The expressions “plasma torch”, “plasma arc”, “plasma gun” and “plasmacutter” are used herein interchangeably and refer to a device forgenerating a direct flow of plasma.

As used herein, the abbreviation “μm” designates micrometers and theabbreviation “nm” designates nanometers.

As used herein, the expression “particle size distribution” or “PSD”defines the relative amount of particles present according to size. Theway PSD is determined in the present disclosure is with either laserdiffraction spectroscopy and/or field emission gun scanning electronmicroscopy (FEG-SEM), where powder is separated on sieves of differentsizes. For example, D90=150 nm indicates that 90% of the particles havea size which is smaller than 150 nm.

EXAMPLES

The examples below are given so as to illustrate the practice of variousembodiments of the present disclosure. They are not intended to limit ordefine the entire scope of this disclosure. It should be appreciatedthat the disclosure is not limited to the particular embodimentsdescribed and illustrated herein but includes all modifications andvariations falling within the scope of the disclosure as defined in theappended embodiments.

Example 1

In this example, a composition comprising nickel-based precursorparticles doped with sulfur was prepared in accordance with anembodiment of the present disclosure.

Briefly, a nickel source and sulfur source were loaded in a furnace andheated to the melting temperatures of sulfur (115-440° C.). Thetemperature was held for sufficient time to allow reaction of liquidsulfur with nickel to form NiS or Ni₃S₂. When the reaction was deemedcomplete, i.e., all sulfur was converted in the form of NiS, thetemperature was raised to the melting temperature of nickel (1400-1500°C.) to obtain a melted mixture. The melted mixture was then gas-atomizedto obtain a composition comprising nickel-based precursor particlesdoped with 0.01 to 0.5 wt. % of sulfur content. The process was repeatedthree times and the results are reproduced in the Table 1, where thecomposition obtained in process #3 was sieved into fine and coarseparticle sub-fractions.

All compositions were analyzed by LECO analysis to determine O, C, N andH contents and by laser diffraction spectroscopy to determine particlesize distribution features.

TABLE 1 S Process content PSD (μm) O C N H # wt. % D10 D50 D90 wt. % wt.% wt. % wt. % 1 0.280 25.7 62.1 103 1.1 0.082 na na 2 0.320 14.5 40.4104 1.5 0.280 na na 3 (fine) 0.033 6.6 14.3 43.2 0.55 0.012 na na 3(coarse) 0.020 22.5 52.7 108.8 0.50 0.005 na na

Example 2

In this example, a composition comprising nickel-based particles dopedwith sulfur was prepared in accordance with an embodiment of the presentdisclosure.

Briefly, a composition comprising nickel-based precursor particles dopedwith 0.01 to 0.5 wt. % of sulfur having a particle size distributionfrom 10 μm to 100 μm was vaporized in an ICP torch (PN50, Tekna PlasmaSystems, Inc.) at a power in the range of 60 to 80 kW under reducingplasma conditions (argon/hydrogen). A scanning electronic microscope(SEM) image was obtained from a sample of the resulting nickel-basedparticles doped with 0.01 to 0.5 wt. % of sulfur and is shown in FIG. 4.The physical properties of these particles are shown in Table 2:

TABLE 2 Physical properties of nickel-based particles doped with sulfurNickel-based particles doped with sulfur BET 7.48 m²/g Oxygen content0.981% D10 0.125 μm D50 0.157 μm

Example 3

In this example, the process of Example 2 was repeated with argoncarrier gas flow rate of 7.5 L/min and additive gas (oxygen) flow rateof 1.0 L/min and quench gas at 8000 L/min. SEM images are shown in FIGS.5A-5C. The particle size distribution (PSD) of the composition beforeclassification is reproduced in Table 3 whereas the PSD of thecomposition post-classification to obtain a D50 of 80 nm is reproducedin Table 4:

TABLE 3 D50 (nm) 88 D90 (nm) 195 D99 (nm) 329 BET (m²/g) 7.77 Particleshape Spherical Carbon content (wt. %) 0.019 Oxygen content (wt. %) 1.1

TABLE 4 Statistics Minimum: 15 nm Maximum: 301 nm Mean: 88.3 nm StdDev.: 43.5 nm Sum: 157728 nm Count: 1786 Under: 0 Over: 0 Accepted:100.0 % Field Count: 4 Field Area: 7584892 nm² Total Area: 30,339570 +06 nm² D10: 42 nm D50: 79 nm D90: 146 nm D01 23 nm D99 227 nm

Example 4

In this example, the process of Example 2 was repeated with argoncarrier gas flow rate of 7.5 L/min and additive gas (oxygen) flow rateof 0.6 L/min and quench gas at 8000 L/min. The particle sizedistribution (PSD) of the composition before classification isreproduced in Table 5:

TABLE 5 D50 (nm) 95 D90 (nm) 169 D99 (nm) 300 BET (m²/g) 5.71 Particleshape Spherical Carbon content (wt. %) 0.050 Oxygen content (wt. %)0.687

Example 5

In this example, the process of Example 2 was repeated with argoncarrier gas flow rate of 5 L/min and additive gas (oxygen) flow rate of1.0 L/min and quench gas at 1200 L/min. The particle size distribution(PSD) of the composition before classification is reproduced in Table 6:

TABLE 6 D50 (nm) 72 D90 (nm) 132 D99 (nm) 213 BET (m²/g) 9.09 Particleshape Spherical Carbon content (wt. %) 0.028 Oxygen content (wt. %) 3

Example 6

In this example, the process of Example 2 was repeated with argoncarrier gas flow rate of 5 L/min and additive gas (oxygen) flow rate of1.0 L/min and quench gas at 1200 L/min. The particle size distribution(PSD) of the composition before classification is reproduced in Table 6:

TABLE 6 D50 (nm) 79 D90 (nm) 146 D99 (nm) 217 BET (m²/g) 8.87 Particleshape Spherical Carbon content (wt. %) 0 Oxygen content (wt. %) 2.6

Example 7

In this example, the process of Example 2 was repeated with argoncarrier gas flow rate of 5 L/min and additive gas (oxygen) flow rate of1.0 L/min and quench gas at 1200 L/min. The particle size distribution(PSD) of the composition before classification is reproduced in Table 7:

TABLE 7 D50 (nm) 72 D90 (nm) 131 D99 (nm) 201 BET (m²/g) 10.04 Particleshape Spherical Carbon content (wt. %) 0 Oxygen content (wt. %) 3.1

In this example, a commercially available product produced by DC-plasmaand commercialized as a composition comprising 80 nm nickel-basedparticles doped with sulfur was analyzed to determine the molecularcontents as well as particle size distribution features (FEG SEM, 7images were analyzed by gridded image analysis, with a total of 2775particles analyzed). The results are reported in Tables 5-6:

TABLE 5 Ni Element (metal basis) C O S Method ICP-MS LECO LECO LECOResult (wt. %) 99.8 0.15 3.10 0.15

TABLE 6 Mean (nm) 104 Std Deviation (nm) 50.8 Dmin (nm) 13 D1 (nm) 18D10 (nm) 43 D50 (nm) 96 D90 (nm) 175 D99 (nm) 242 Dmax (nm) 298 <20 nm(%) 1.66 >350 nm (%) 0

Example 8

In this example, the sintering behavior of nickel-based particles dopedwith sulfur obtained in Example 3 (sample 2) was compared to thesintering behavior of nickel-based particles without doping agent(samples 1 and 3). The results are produced in Table 7 as well as inFIG. 15.

TABLE 7 Tstart Tend Number CTE_(100° C.) ^(300° C.) Number ° C. ° C. ofsteps ppm/K 1 234 621 3 15.5 2 306 994 3 . . . 5 3 153 812 5 13.1

These results show that in the composition, the sulfur is effectivelyincorporated into the nickel-based particles, rather than having acomposition with separate sulfur particles and separate nickelparticles, since the sintering behavior is changed with the presence ofsulfur doping agent.

It should be appreciated that the disclosure is not limited to theparticular embodiments described and illustrated herein but includes allmodifications and variations falling within the scope of the subjectmatters as defined in the appended claims.

All references cited in this specification, and their references, areincorporated by reference herein in their entirety where appropriate forteachings of additional or alternative details, features, and/ortechnical background.

While the disclosure has been particularly shown and described withreference to particular embodiments, it will be appreciated thatvariations of the above-disclosed and other features and functions, oralternatives thereof, may be desirably combined into many otherdifferent systems or applications. Also, that various presentlyunforeseen or unanticipated alternatives, modifications, variations orimprovements therein may be subsequently made by those skilled in theart which are also intended to be encompassed by the embodimentsdescribed herein.

Other examples of implementations will become apparent to the reader inview of the teachings of the present description and as such, will notbe further described here.

Note that titles or subtitles may be used throughout the presentdisclosure for convenience of a reader, but in no way these should limitthe scope of the invention. Moreover, certain theories may be proposedand disclosed herein; however, in no way they, whether they are right orwrong, should limit the scope of the invention so long as the inventionis practiced according to the present disclosure without regard for anyparticular theory or scheme of action.

It will be understood by those of skill in the art that throughout thepresent specification, the term “a” used before a term encompassesembodiments containing one or more to what the term refers. It will alsobe understood by those of skill in the art that throughout the presentspecification, the term “comprising”, which is synonymous with“including.” “containing,” or “characterized by,” is inclusive oropen-ended and does not exclude additional, un-recited elements ormethod steps.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention pertains. In the case of conflict, thepresent document, including definitions will control.

As used in the present disclosure, the terms “around”, “about” or“approximately” shall generally mean within the error margin generallyaccepted in the art. Hence, numerical quantities given herein generallyinclude such error margin such that the terms “around”, “about” or“approximately” can be inferred if not expressly stated.

Although various embodiments of the disclosure have been described andillustrated, it will be apparent to those skilled in the art in light ofthe present description that numerous modifications and variations canbe made. The scope of the invention is defined more particularly in theappended claims.

1-180. (canceled)
 181. A multilayer ceramic capacitor (MLCC) comprising:a plurality of dielectric layers and electrode layers arranged to form astack were the dielectric layers and the electrode layers alternate,wherein one or more of the electrode layers comprises a compositionincluding metal-based particles having a D50≤80 nm, wherein metal-basedparticles having a size >350 nm represent less than 1 ppm.
 182. The MLCCof claim 181, wherein the metal-based particles have a D99≤230 nm. 183.The MLCC of claim 181, wherein the metal-based particles have a D90≤150nm.
 184. The MLCC of claim 181, wherein the metal-based particlesfurther comprise 0.1 wt. % or more of oxygen content.
 185. The MLCC ofclaim 183, wherein the metal-based particles comprise 5 wt. % or less ofoxygen content.
 186. The MLCC of claim 181, wherein the metal-basedparticles further comprise an oxidation layer on at least a portion of asurface of the particles.
 187. The MLCC of claim 186, wherein theoxidation layer has a thickness of less than about 5 nm.
 188. The MLCCof claim 181, wherein the metal in the metal-based particles is nickel.189. The MLCC of claim 181, wherein the metal in the metal-basedparticles is silver, copper, lead, palladium, platinum, gold, cobalt,iron, cadmium, zirconium, molybdenum, rhodium, ruthenium, tantalum,titanium, tungsten, zirconium, or niobium.
 190. The MLCC of claim 181,wherein the metal-based particles are doped with sulfur.
 191. The MLCCof claim 190, wherein the sulfur has a concentration of from about 0.01to about 0.5 wt. %.
 192. The MLCC of claim 181, wherein on a crosssection of the stack in a direction perpendicular to a mounting surfaceof the MLCC, two adjacent dielectric layers separated by an electrodelayer have an average distance d of <500 nm.
 193. The MLCC of claim 181,wherein the one or more of the electrode layers has from 3 to 5metal-based particles stacked in a direction perpendicular to the stack.194. A multilayer ceramic capacitor (MLCC) comprising: a plurality ofdielectric layers and electrode layers arranged to form a stack wherethe dielectric layers and the electrode layers alternate, wherein one ormore of the electrode layers comprises a composition includingmetal-based particles having a D50≤80 nm and a Dmax<350 nm.
 195. TheMLCC of claim 194, wherein the Dmax≤200 nm.
 196. The MLCC of claim 194,wherein the metal-based particles have a D90≤150 nm.
 197. The MLCC ofclaim 194, wherein the metal-based particles have a D99≤230 nm.
 198. TheMLCC of claim 194, wherein the metal-based particles further comprise0.1 wt. % or more of oxygen content.
 199. The MLCC of claim 198, whereinthe metal-based particles comprise 5 wt. % or less of oxygen content200. The MLCC of claim 194, wherein the metal-based particles furthercomprise an oxidation layer on at least a portion of a surface of theparticles.
 201. The MLCC of claim 200, wherein the oxidation layer has athickness of less than 5 nm.
 202. The MLCC of claim 194, wherein themetal in the metal-based particles is nickel.
 203. The MLCC of claim194, wherein the metal in the metal-based particles is silver, copper,lead, palladium, platinum, gold, cobalt, iron, cadmium, zirconium,molybdenum, rhodium, ruthenium, tantalum, titanium, tungsten, zirconium,or niobium.
 204. The MLCC of claim 202, wherein the metal-basedparticles are doped with sulfur.
 205. The MLCC of claim 204, wherein thesulfur has a concentration of from about 0.01 to about 0.5 wt. %. 206.The MLCC of claim 194, wherein on a cross section of the stack in adirection perpendicular to a mounting surface of the MLCC, two adjacentdielectric layers separated by an electrode layer have an averagedistance d of <500 nm.
 207. The MLCC of claim 194, wherein the one ormore of the electrode layers has from 3 to 5 metal-based particlesstacked in a direction perpendicular to the stack.